This research intends to develop a Nanoliter Tear Osmometer for the detection of the presence and degree of dry eye. It is estimated that 40-60 million Americans have dry eye symptoms. Prescription pharmaceuticals are appearing on the market to treat dry eye yet methods for diagnosis and monitoring treatment remain problematic. This Phase I research will make use of a new technology for analyzing tear osmolarity, which is popularly accepted by experts in the field as an indicator of the occurrence and severity of dry eye. Specifically, the research will develop an instrument to analyze nanoliter volumes of tears that offers quick, reliable, and an accurate measure of osmolarity. It is the intention of research team to develop a system that is simple to use and requires no special training thereby making it a suitable device for the clinical ophthalmologist or optometrist. The technological approach proposed is unique and innovative, as it overcomes many of the shortcomings of conventional osmolarity measurements. Commercial potential for such a device is high, since it is projected that cost in production will be in-line with other instruments purchased by clinicians. The pharmaceutical industry has invested large dollar amounts into treatment of dry eye and expect large returns in the next several years. With this introduciton of prescription treatment of dry eye it may become a necessity to have proper a diagnostic tool, and the osmometer proposed has attributes ideally suited for clinical examinations. The use of existing proven technology and applying it to tear osmolarity forms the basis of this Phase I research. Several factors on the effectiveness of measuring tear osmolarity will be examined, including resolution, sensitivity, and overall performance. The research will conclude with an IRB approved study.